In current cellular networks, three functions are performed in order to establish a call or connection to a mobile unit or mobile in such a network: (1) locating the mobile; (2) handling any implicit services to which a user may have subscribed; and (3) establishing the connection. These functions, may be referred to, respectively, as mobile location, call control, and connection control. In some networks, authentication functions are also performed.
During registration of a mobile in current cellular networks, a user profile is sent from a home network to a Visitors' Location Register (VLR) in the network in which the mobile user is currently located. A Mobile Switching Center (MSC) then obtains the user's profile from the VLR either during registration or during call delivery in order to provide signalling services for the mobile user. One disadvantage of this technique is that sending the user profile requires the sharing of competitive information between different networks. A second disadvantage is that signalling traffic is generated even when the mobile is not involved in a call.
Also, in typical current cellular networks, the function of locating the mobile is performed, in a sequential manner, prior to the function of performing call control and establishing the connection. The sequential nature of current procedures leads to long setup delays.
Finally, in typical current cellular networks, the MSC, is required to be an anchor for the duration of the call. The MSC thus remains involved for the duration of a call even if there exists a more efficient route for the user information path.